Given the sets $A = \{1, 2, 3\}$,$B = \{3, 4\}$,and $C = \{4, 5, 6\}$,find $A \cup (B \cap C)$.

Let $A = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10\}$ and $B = \{2, 3, 5, 7\}$. Find $A \cap B$ and hence show that $A \cap B = B$.

If $A=\{1, 2, 3, 4\}, B=\{3, 4, 5, 6\}, C=\{5, 6, 7, 8\}$ and $D=\{7, 8, 9, 10\}$,find $A \cup C$.

Find the union of each of the following pairs of sets:
$A = \{ x : x \text{ is a natural number and a multiple of } 3 \}$
$B = \{ x : x \text{ is a natural number less than } 6 \}$

If $A = \{3, 6, 9, 12, 15, 18, 21\}$,$B = \{4, 8, 12, 16, 20\}$,$C = \{2, 4, 6, 8, 10, 12, 14, 16\}$,and $D = \{5, 10, 15, 20\}$,find $B - C$.

Let $A$ and $B$ be two sets,then $(A \cup B)' \cup (A' \cap B)$ is equal to